You do not focus in meditation. It is the exactly opposite of that. Meditation is not concentration, it is de-concentration. You just have to relax. Ofcourse, high energy is needed to be able to relax, hence it is preceded by Pranayama and Kriya Yoga.
Q – What is Meditation?
Sri Sri Ravi Shankar – Many believe that meditation is concentration
or that it takes a lot of effort. Meditation is not concentration. It
is the opposite of concentration. If you have to drive anywhere, you
need concentration. If you simply have to relax at home, there need
not be any effort. You don’t need concentration.
Meditation is deep relaxation and no concentration. So, if thoughts
come during meditation, we do not try to chase them. The more we chase
them, the more they come. If you want to get rid of a thought, it will
not be easy. It will come back in a stronger way.
So, we have another strategy. If bad thoughts come to us, we hug them,
we shake hands with them. Then, they disappear. If good thoughts come,
we give them a hug, then they become quiet. We do not try to stop any
thoughts, it’s an effortless practice.
Taken from: http://www.artofliving.org/meditation/srisri-meditation/sound-to-silence
I was lucky to be introduced to meditation at the age of 17. I would recommend that rather than doing it on your own, you learn it from a proper teacher. There are many such good organisations teaching meditation - Art of Living foundation, Isha Yoga foundation etc.
Hope this helps! :)